. >>> reporter: cal grad jill costello was 22 when she died from lung cancer in 2010. it's how she lived that lives on. >> i do think that last year of jill's life and although it was her most difficult and most challenging, you know, many ways it could be the best year of her life. she did so many wonderful, amazing things and truly lived life to its fullest. >> best friend since kindergarten in san francisco, jill costello and chelsea harrison share another bond. >> i'm using my lungs. >> the 24-year-old harvard grad is spreading a simple message. anyone can get lung cancer, even nonsmokers like jill. >> the reason i'm doing this is for jill and i have that drive and i think she is watching out for us and making sure that wie make it to the end safely. >> kelsey took off from times square on july 30 and has spent four months on the road. >> go giants. >> do you think you will be there today? >> sidney ford who rode krewe with jill at cal as soon as having that person telling you can do this. >> when jill lost her hair to chemo sidney was by her side. >> i said if you